Small Asteroid Zips Close By Earth as Astronomers Watch

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A small asteroid passed close
by Earth today (Oct. 12), flying within the orbit of the moon while astronomers
watched to see if the encounter caused any quakes on the space rock.

The asteroid 2010 TD54 made
its closest approach to Earth at 6:51 a.m. EDT (1051 GMT), when it passed
within about 28,000 miles (45,000 km) of the planet. It was flying over Southeast
Asia, near Singapore, at the time. [ Photo
of Asteroid 2010 TD54 Flyby.]

Astronomers at the Massachusetts
Institute of Technology in Boston used a remote link with a NASA Infrared
Telescope Facility in Hawaii to observe
the small asteroid, which was up to 33 feet (10 meters) across.

Asteroid 2010 TD54 zips by

There was no risk of the
asteroid entering
Earth's atmosphere or exploding, and it was too small to survive the fiery
entry even if it did. But that did not keep astronomers from taking a close
look as the space rock sailed by.

"For 2010 TD54, we want
to learn its basic composition and to watch whether its close encounter with
the Earth causes any changes," astronomer Richard Binzel, a professor of
planetary science at MIT, told SPACE.com.

Small asteroids that are
previously unknown, like 2010 TD54, often pass by Earth.

An asteroid about 16.5 feet
(5 meters) across can be expected to pass Earth inside the orbit of the moon
about once a day, NASA scientists said. They typically enter Earth's atmosphere
once every two years or so, they added. There are an estimated 30 million
unknown asteroids in our solar system.

Bigger asteroids about 460
feet (140 meters) wide can cause widespread damage around their impact sites,
but for global devastation much larger space rocks would have to strike Earth.

Binzel said he and his
colleagues study asteroids by observing them in visible and near-infrared
wavelengths of light, which allows them to determine which minerals are
present.

"The presence and
strength of mineral absorption bands over these wavelengths allow us to
interpret their compositions and directly relate these compositions to known
meteorite samples, whenever possible," he said.

NASA regularly tracks
asteroids and comets that fly near Earth as part of its Near-Earth Object
Observations program, which uses a network of ground and space telescopes. The
program has tracked 85 percent of the largest asteroids that fly near Earth and
15 percent of asteroids in the 460-foot class, according to the latest report.

NASA also plans to send
astronauts to an asteroid by 2025 under new space plan ordered by President
Obama. The mission could help scientists better understand the composition of
asteroids, as well as develop better methods of deflecting them before they
pose a threat to Earth, space agency officials have said.